In many industrial and commercial environments and particularly in the operation of motor vehicles and stationary machinery, the necessity of providing thermal control of fluids requires the use of fluid heat exchangers that reliably operate over wide temperature ranges and heat capacities. Typically, the prior art has developed complex paths for at least two fluids to prolong the heat exchange relation between the fluids and this has correspondingly complicated the manufacturing steps required to produce the structures and invariably increased the cost of manufacturing such heat exchange devices. In many cases, design simplification to reduce manufacturing steps and costs often results in limiting the temperature range of the fluids that the devices are capable of handling. In other cases, manufacturers have resorted to the use of expensive materials that are frequently difficult to work with to improve the performance of the heat exchange structures. Other solutions have involved simply increasing the surface areas of the heat exchanger which the fluids contact although isolated from each other, This obviously constrains the locations where the exchanger is able to be installed particularly where the thermal control is needed in connection with the operation of stationary machinery or of a power source such as an internal combustion engine that has been previously constructed. In still other attempts, manufacturers have resorted to the use of pumps to improve throughput but these increase the the power consumption of the apparatus and this solution will correspondingly increase the cost of apparatus both in terms of construction and operation.